Improving The Sustainability of Solar Panel Production

Improving The Sustainability of Solar Panel Production

By Imogen Pass of Ossila Ltd.

Solar technology is on track to become the largest renewable energy source by 2029¹. As part of this growth, new solar technologies are gaining momentum. Many next-generation materials, like perovskites and organic photovoltaics, can leverage solution-processed manufacturing, which is cheaper, less energy intensive, and produces less waste.

Environmental Challenges in Solar Panel Production

Crystalline silicon solar panels currently dominate 98% of the global solar market² but their production is energy intensive. For silicon solar panels to achieve high efficiencies, the silicon must be ultra-pure, which requires several important manufacturing steps:

1. Silicon is extracted from silicon dioxide in an electrode arc furnace that reaches 1500-2000 °C². This process removes oxygen to produce metallurgical-grade silicon with a 98-99% purity.
2. The resulting silicon undergoes further purification at high temperatures. The impure silicon ingot is passed through a heated zone, above the melting point of silicon (1415 °C), multiple times.
3. The final silicon ingots are sliced into wafers using diamond saws. It is these wafers that are used to fabricate the solar cells. Up to 35% of the silicon is lost as dust³. The dust is difficult to recycle, so most of this waste goes to landfill.

As a result of this process, solar panel production remains carbon intensive because these high-energy manufacturing processes are still primarily powered by fossil fuels. While solar panels only need to operate for 4-8 months to offset their manufacturing emissions, this does not reverse the emissions released during their production.

Improvements in manufacturing techniques have cut the emissions intensity of production by nearly 50% since 2011, but overall CO₂ emissions from solar PV manufacturing have almost quadrupled as the industry has expanded⁴. As manufacturing capacity grows further, it will becoming increasingly important for the solar industry to prioritize, reduce, and take responsibility for the environmental impact of solar panel production.

The Promise of Solution-Processing

Emerging solar materials, such as perovskites, organic photovoltaics, and quantum dot solar cells, offer an alternative to traditional silicon panels. These materials enable solution-processing techniques, like spin coating or slot-die coating, which have:

• Lower energy requirements as solution-processing techniques are compatible with materials that can be processed in ambient conditions. Many solution-processable materials have a higher defect tolerance, meaning they do not require the same high-purity levels as silicon, reducing the number of processing steps required.
• Minimal material waste because, unlike silicon which requires cutting and shaping, solution-processed materials can be coated directly onto substrates in thin layers with control and precision.

Increasing the adoption of next-generation solar technologies across the commercial market would provide opportunities to transition to solution-processing as a key part of the solar panel manufacturing process.

The Production Chain

Alongside manufacturing techniques, there are other opportunities to reduce the environmental impact within the solar panel production chain:

1. Implementing Circular Economy Approaches

• Improving recycling technologies for end-of-life solar panels can recover valuable materials, such as silver, indium, and gallium, reducing the need for new raw materials.
• Establishing industry-wide regulations for panel disposal to prevent hazardous waste accumulation.

2. Decentralizing Solar Panel Production

• Reducing dependence on single manufacturing hubs, such as China which controls over 80% of all solar panel manufacturing stages⁴, to lower transportation-related carbon emissions and improve supply chain resilience.
• Developing regional manufacturing capacity can also create economic opportunities and reduce reliance on existing fossil fuel-powered production centres and infrastructure.

Towards a Greener Solar Industry

Renewable energy plays a vital role in helping countries worldwide achieve their net-zero emissions targets. As solar power capacity continues to grow to meet these goals, it is crucial to acknowledge the environmental impact of solar panel manufacturing. To create a truly sustainable solar industry, production processes must align with sustainability principles and emissions reduction targets, ensuring that clean energy solutions are environmentally responsible from start to finish.

Resources used:

1. https://www.iea.org/energy-system/renewables/solar-pv
2. https://www.pveducation.org/pvcdrom/manufacturing-si-cells/refining-silicon
3. https://cen.acs.org/environment/recycling/Solar-panels-face-recycling-challenge-photovoltaic-waste/100/i18
4. https://www.iea.org/reports/solar-pv-global-supply-chains/executive-summary

About the Author

Imogen writes articles that make science accessible with the knowledge and help of Ossila’s experts. At Ossila, we specialize in lab equipment and materials that are used in solar cell and display technology research, driving the development of higher efficiency solar panels, flexible OLED screens, wearable solar-powered devices, battery technologies, and more.